Spatiotemporal Variability of Tropical Cyclone-Induced Ocean Heat Uptake and Its Effect on Ocean Heat Content

Tropical cyclones (TCs) can pump heat downward into the ocean through inducing intense vertical mixing. Many efforts have been made to estimate the TC-induced ocean heat uptake (OHU), but spatiotemporal variability of TC-induced OHU remains unclear. This study estimates the TC-induced OHU, which takes into account the heat loss at the air-sea interface during TC passage compared to previous studies and investigates the spatiotemporal variability of TC-induced OHU and its potential impacts on ocean heat content (OHC) during the period 1985-2018. It is found that the spatial distribution of OHU is inhomogeneous, with the largest OHU occurring in the northwest Pacific, and category 3-5 TCs contribute approximately 51% of the total global OHU per year. The annually accumulated TC-induced OHUs in the regional basins exhibit pronounced interannual variability, which is closely related to the TC power dissipation index (PDI). By decomposing PDI into TC intensity, frequency, and duration, we find that the TC characteristics influencing OHU variability vary by basin. Correlation analyses suggest that the interannual variations of OHUs are linked to El Nino-Southern Oscillation (ENSO). In addition, the OHU might have the potential to influence OHC variability, espe-cially in the equatorial eastern Pacific where there are significant positive correlations between the OHU and OHC with lags of 2-6 months. This has an important implication that TC-induced OHU might have potential effects on ENSO evolution.

Automated summary

Tropical cyclones can transfer heat downward into the ocean, and this study investigates the spatiotemporal variability of this heat transfer and its potential impacts on ocean heat content. It finds that the distribution of heat transfer is uneven, with the greatest heat transfer occurring in the northwest Pacific. Interannual variability of heat transfer is closely related to the characteristics of tropical cyclones, and correlation analyses suggest a link to El Nino-Southern Oscillation. The study also suggests that heat transfer might have potential effects on ENSO evolution.